// FILE. . . . . d:/hak/hlt/src/hlt/fot/Signature.java
// EDIT BY . . . Hassan Ait-Kaci
// ON MACHINE. . Hak-Laptop
// STARTED ON. . Sat Jul 14 07:23:54 2018
package hlt.fot;
import hlt.language.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
/**
* This is a class containing all the information concerning a
* term-constructor signature as a set of Functor objects.
*
* @see Functor
* @see FirstOrderTermStructure
*
* @version Last modified on Wed Nov 13 14:29:44 2019 by hak
* @author Hassan Aït-Kaci
* @copyright © Hassan Aït-Kaci
*/
public class Signature
{
protected int size = 0;
public int size ()
{
return size;
}
public boolean isEmpty ()
{
return size == 0;
}
/**
* Constructs a new empty signature.
*/
public Signature ()
{
}
/**
* Contains the functors.
*/
protected ArrayList functors;
/**
* Returns the functors as an ArrayList of Functor
* objects.
*/
public ArrayList functors ()
{
if (functors == null)
return functors = new ArrayList();
return functors;
}
/**
* Returns the functor at position functorPosition, where 1
* ≤ functorPosition ≤ signature.size(). If this
* signature is empty, returns null.
*/
public Functor functor (int functorPosition)
{
// HACK: Should NEVER happen!
// if (functorPosition == 0) functorPosition = 1;
return (Functor)functors().get(functorPosition-1);
}
/**
* Contains an access-by-name table;
*/
protected HashMap functorNameTable;
protected HashMap functorNameTable ()
{
if (functorNameTable == null)
return functorNameTable = new HashMap();
return functorNameTable;
}
/**
* Resets this signature to empty.
*/
public void clear ()
{
functors.clear();
functorNameTable.clear();
}
/**
* Returns the functor called name in this signature if it is
* not empty; undefined otherwise (returns null).
*/
public Functor functor (String name)
{
return (Functor)functorNameTable().get(name);
}
/**
* Returns the functor name/arity if it is already
* defined in this signature, adding it to this signature if not
* already there. If this functor's name was already defined but with
* a different arity, throws a BadFunctorArityException. If
* all ok, returns the functor.
*/
public Functor functor (String name, int arity)
{
Functor functor = (Functor)functorNameTable().get(name);
if (functor == null)
{ // this is a new functor: need to create it and add it to this signature
functor = new Functor(size++,name,arity,this);
functors().add(functor);
functorNameTable().put(name,functor);
}
else
if (arity != functor.arity())
throw new BadFunctorArityException(functor,arity);
return functor;
}
/* ************************************************************************ */
public Iterator iterator ()
{
return functors().iterator();
}
/* ************************************************************************ */
/**
* Return a string form for this signature.
*/
public String toString ()
{
return setForm();
}
protected String setForm ()
{
StringBuilder form = new StringBuilder("{");
for (int i=0; i